Process for producing hollow forging with frusto conical exterior andinterior surfaces

ABSTRACT

A hollow open-ended frusto-conical forging having substantially uniform wall-thickness from end-to-end, for use as a reducer in pipe lines and the like, is made by first obtaining a hollow work-piece having a frusto-conical exterior surface and substantially cylindrical interior surface. This work-piece is heated to forging temperature and placed around a horizontally disposed cylindrical mandrel which is supported on the bed of a power press and the platen of the power press is pressed against the major portion of the work-piece which is internally supported by the mandrel to obtain a tapering reduction in the major portion of the work-piece thereat. The platen is then raised and the work-piece is partially rotated to position an immediately adjacent segment of the work-piece between the platen and mandrel. These steps are continued, with the intermediate raising of the platen and partial rotation of the work-piece until the inside and outside diameters of the work-piece are of acceptable dimensions throughout a 360* arc. The power press is then adjusted to increase the lowermost position of the platen with respect to the mandrel, and the steps described are repeated throughout a 360* arc as before. This is continued until the final hollow product with frusto-conical exterior and interior surfaces of the desired dimensions has been obtained.

iluited States Patent 1191 Moore, Sr.

[ June 26, 1973 22] Filed: Nov. 12, 1 971 [21] Appl. No.: 198,239

[52] US. Cl 72/370, 72/375, 72/377 [51] Int. Cl B21k 21/10 [58] Field ofSearch 72/375, 376, 377,

' [56] References Cited UNITED STATES PATENTS I 6/1972 Muller et al.72/421 7/1926 Larkin 72/340 Primary Examiner-Lowell A. LarsonAttorney-Robert U. Geib, Jr.

[5 7] ABSTRACT A hollow open-ended frusto-conical forging havingsubstantially uniform wall-thickness from end-to-end,

for use as a reducer in pipe lines and the like, is made by firstobtaining a hollow work-piece having a frustoconical exterior surfaceand substantially cylindrical interior surface. This work-piece isheated to forging temperature and placed around a horizontally disposedcylindrical mandrel which is supported on the bed of a power press andthe platen of the power press is pressed against the major portion ofthe work-piece which is internally supported by the mandrel to obtain atapering reduction in the major portion of the workpiece thereat. Theplaten is then raised and the workpiece is partially rotated to positionan immediately adjacent segment of the work-piece between the platen andmandrel. These steps are continued, with the intermediate raising of theplaten and partial rotation of the work-piece until the inside andoutside diameters of the work-piece are of acceptable dimensionsthroughout a 360 arc. The power press is then adjusted to increase thelowermost position of the platen with respect to the mandrel, and thesteps described are repeated throughout a 360 are as before. This iscontinued until the final hollow product with frusto-conical exteriorand interior surfaces of the desired dimensions has been obtained.

3 Claims, 4 DrawingFigures PATENIEB M26 I975 Char/e3 H. Moore IN VENTORATTORNEY PROCESS FOR PRODUCING HOLLOW FORGING WITH FRUSTO-CONICALEXTERIOR AND INTERIOR SURFACES There is considerable demand, for manyindustrial applications for frusto-conical reducers for pipe lines,such, for example, as reducing a 24 inch pipe to a inch pipe, or even 18inches, a 20 inch pipe to an 18 inch pipe or even 16 inch pipe to a 14inch, etc.

As pipe wall thicknesses vary from low schedules to high schedules from108 to Schedule 160 (the wallthickness of 24 inch pipe in Schedule 108is .258 inch and in Schedule 160 the wall thickness of 24 inch pipe is2.343 inches) it will be observed that in the larger schedules thesereducers become massive forgings, and heretofore have been veryexpensive to produce.

Prior to the present invention such frusto-conical articles (reducersand the like) were mostly produced either by l. pressing a round barinto a conical die so as to upset the metal downwardly into the die,then center punching a cylindrical bore to the small end of thework-piece, and finally machining the interior of thework-piece toproduce the desired frustoconical shape and size 2. machining acylindrical work-piece on both the interior and exterior to producefrusto-conical surfaces thereon which is prohibitively expensive 3.pressing a tapered plug into a necessarily heavy (due to thewall-thinning on the big end) cylindri cal work-piece which is disposedin a special and expensive frusto-conical die which is very limited asto the shape and size of the product it will produce, i.e., onlyfeasible in the event of a sizeable run" of the desired product. Evenso, there remains considerable metal to be machined from the outside.

The difficulty with respect to this third prior art method is quiteapparent, while the problem with respect to the first two is, of course,the very high cost of machining to remove or hog large areas of metal asdistinguished from the displacement thereof by forging.

It is among the objects of the present invention to provide a highlyefficient and relatively simple and inexpensive process for producingfrusto-conical forgings of the type referred to. v

Another object is the provision of a process of the type described whichmay be effectively and inexpensively utilized for a single product aswell as for a large run.

Still another object is the attainment of the foregoing advantages withthe use of equipment of existing design.

The foregoing and other objects and advantages will become more readilyunderstood from the following description and annexed drawings, whereinlike reference characters designate like parts, and wherein:

FIG. 1 is a perspective of an example of a cylindrical work-piece whichis obtained as a preliminary to prac ticing the process of theinvention, and showing its dimensions for comparative purposes.

FIG. 2 is a schematic view illustrating a conventional heavy duty press,with stationary horizontal bed and vertically movable platen shown inthe raised position, together with a pair of mandrel supportswhich reston the bed and between them support a round elongate mandrel, and thework-piece as mounted on the mandrel prior to the commencement of theforging operation.

FIG. 3 is another schematic view, but illustrating the work-piece bothprior to the forging operation (in dotted lines) and as completelyforged (solid lines and cross-hatched).

FIG. 4 is a sectional elevation of the work-piece after it has beensubjected to the process of the invention, and illustrating therespective dimensions.

Referring more particularly to the drawings, the numeral 2 designatesthe bed or bottom of a heavy duty press, while the platen thereof isshown at 3, being in the raised position.

Disposed upon the bed or bottom 2 of the press is a pair of spacedparallel mandrel supports 4, which between them support a round mandrel5 of substantially uniform diameter, and which, for purposes of enhancedstrength, is shown as having a solid interior.

In the manner well-known in the art the distance the platen 3 may bemoved downwardly toward the bed or bottom of the press is determined bya plurality of superposed blocks which act as shims, the same beingschematically illustrated in FIG. 2, it being understood, however, thatthey may be disposed anywhere between the platen and the bed which willachieve the desired result.

As indicated earlier herein, there is first obtained, as bypipe-punching, a cylindrical work-piece A of roughly predeterminedheight and inside and outside diameter, which is machined on the outsideso as to provide a frusto-conical exterior, and which is heated toforging temperature; or is forged to this exterior contour in a die andis then center-hole punched. In either event the inner wall of thework-piece A is cylindrical.

In FIG. 1 an example of the immediate foregoing is given as:

Height 26" Inside Diameter 15.5" Outside Diameter Large End 25.75"Outside Diameter Small End 22.625" (machined) Weight 3417.00 lbs.

Referring to FIG. 2, the cylindrical work-pieceA machined or forged toan outside taper in diameter, as described hereinbefore, and as heatedto forging temperature, is moved into position between the spacedparallel mandrel supports 4 with the round mandrel 5 inserted throughit, whereby it is supported by the mandrel above the bed or bottom 2 ofthe press.

As will be observed, the diameter of the round mandrel 5 is slightlyless than the inside diameter of the cylindrical work-piece A, and forthe example given herein was 15 inches.

With the work-piece A supported in the position described, tlne platen 3of the heavy duty press is lowered to a suitable extent by utilizing thecontrols for such positioning which are conventional equipment onapparatus of this type. As an alternative, spacer blocks or large shims(not shown) may be disposed on the upper extremities of the U-shapedvertically extending mandrel supports 4 operating against the internalsupport of the round mandrel 5, to make an appreciable reduction in thewall thickness of the work-piece at that point.

The platen 3 is then raised, and the work-piece A is partially rotated,either by hand (as with pikes which are standard foundry equipment) orby one of several types of machines which are adapted to such purposes.

After the partial rotation of the work-piece A, the platen 3 is againlowered into contact therewith, making an adjoining reduction in thewall-thickness which is similar to the one previously made.

This forging operation with the raising of the platen and intermittentpartial rotation of the work-piece is repeated until the work-piece hasbeen rotated throughout a 360 arc.

After a complete series of reductions or bites have been taken in thewall of the work-piece throughout a 360 arc, the power press is soadjusted as to increase the lower limit to which the platen will bemoved. Such power press controls are entirely conventional, but powerpresses without the same may be utilized by simply adopting theexpedient of providing spacer blocks for disposition atop the upperextremities of the U- shaped upper ends of the mandrel supports 4.

According to the foregoing, the wall-thickness of the small end of thework-piece need undergo no change, and the entire operation concludedwhen the wallthickness at both the small end and the big end are thesame.

As an example, each individual reduction in the thickness of the wall ofthe work-piece A may be approximately l inch and extend over an area inwidth of approximately 6 inches until all 26 inches have been coveredthroughout a 360 arc.

It has been found practical to effect the desired total reduction in thewall-thickness of the work-piece A without resort to the expense anddelay of re-heating.

The work-piece A, after being completely forged in accordance with theteachings of the present invention, is represented at B in FIG. 4. Aswill be observed in this Figure, the dimensions of the frusto-conicalforging B, for the example given, are as follows:

Prior to Finish Machining Height 26" Inside Diameter Large End 31.5

Inside Diameter Small End 19.5" Outside Diameter Large End 375" OutsideDiameter Small End 25.5" Weight 3417 pounds To Finish 32" ID. X 20" LD.X

2.5" Wall as a cone.

As will be observed from the foregoing, a single setup of mandrelsupports 4 and round mandrel 5 may be effectively utilized to obtainfrusto-conical forgings or varying sizes and tapers.

It is interesting to note that the weight loss due to the initialmachining was only 456 pounds (the difference between 3,873 pounds and3,417 pounds) to get workbetween 5,796 pounds and 3,417 pounds).

In producing the completed frusto-conical forging of the example givenherein, the following calculations are taken into consideration in orderto develop the dimension of work-piece A, as shown in FIG. 1.

CD. at Big End 1.0. at Big End CD. at Small End ID. at Small End PipePunching 15.5" X

Plus 1" at Big End (see 7 V V ,7.

above) 94.42 1b plus 60.07 1h (1 at Big End) 147.88 I 25.75" diameter(FIG.

113.58 lb 22.675 diameter (small end of work-piece A in FIG. 1)

Having thus described the invention what I claim as new and desire tosecure by letters patent is:

I claim:

1. The process for making an open-ended; frustoconical hollow-forginghaving substantially uniform wall-thickness from end-to-end for use asreducers in pipe lines and the like; which consists essentially ofobtaining a work-piece of frusto-conical exterior and substantiallyuniform inside diameter from end-toend heating the said work-piece toforging temperature placing the work-piece while heated to forgingtemperature on a horizontally extending cylindrical mandrel which is ofsmaller outside diameter than the inside diameter of the work-piece andwhile the mandrel is supported on the bed of a press pressing the platenof the press against the exterior of that portion of the work-piecewhich is internally supported by the mandrel raising the platenpartially rotating the work-piece repeating the application of pressureand the raising of the platen while intermittently partially rotatingthe work-piece through 360 until the inside and outside diameters are ofacceptable dimensions extending the adjustment of the platen toward themandrel;

and

continuing the foregoing operational steps until the desired internaland external dimensions have been obtained.

2. The process of claim 1 wherein the exterior surface of the startingwork-piece is machined on the outside to provide a frusto-c'onicalsurface prior to heating to forging temperature.

would have required a starting weight of 5,796 pounds, 6

and a resultant weight loss of 1,379 pounds (difference 3. The processof claim 1 wherein the initial workpiece is forrned in a die.

II I. I l t

1. The process for making an open-ended; frusto-conical hollowforginghaving substantially uniform wall-thickness from end-toend for use asreducers in pipe lines and the like; which consists essentially ofobtaining a work-piece of frusto-conical exterior and substantiallyuniform inside diameter from end-to-end heating the said work-piece toforging temperature placing the work-piece while heated to forgingtemperature on a horizontally extending cylindrical mandrel which is ofsmaller outside diameter than the inside diameter of the work-piece andwhile the mandrel is supported on the bed of a press pressing the platenof the press against the exterior of that portion of the work-piecewhich is internally supported by the mandrel raising the platenpartially rotating the work-piece repeating the application of pressureand the raising of the platen while intermittently partially rotatingthe work-piece through 360* until the inside and outside diameters areof acceptable dimensions extending the adjustment of the platen towardthe mandrel; and continuing the foregoing operational steps until thedesired internal and external dimensions have been obtained.
 2. Theprocess of claim 1 wherein the exterior surface of the startingwork-piece is machined on the outside to provide a frusto-conicalsurface prior to heating to forging temperature.
 3. The process of claim1 wherein the initial work-piece is formed in a die.